Process for producing a particulate nanocomposite material

Abstract

The present invention relates to a process for producing a particulate nanocomposite material, in which the particles of the nanocomposite material comprise a) at least one inorganic or organo(semi)metallic phase which comprises at least one (semi)metal M; and b) at least one organic polymer phase. The invention also relates to the nanocomposite materials obtainable by this process. The process comprises the polymerization of at least one monomer MM which has at least one first cationically polymerizable monomer unit A which has a metal or semimetal M, and at least one second cationically polymerizable organic monomer unit B which is joined to the polymerizable unit A via at least one, e.g. 1, 2, 3, or 4, covalent chemical bond, under cationic polymerization conditions under which both the polymerizable monomer unit A and the polymerizable unit B polymerize with breakage of the bond or bonds between A and B, wherein the polymerization is performed in an aprotic solvent in which the nanocomposite material is insoluble, in the presence of at least one polymerization initiator and of at least one further substance selected from α) at least one surface-active substance and β) at least one particulate material.

The invention claimed is: 
     
       1. A process for producing a particulate nanocomposite material which comprises particles that comprise
 a) at least one inorganic or organo(semi)metallic phase which comprises at least one (semi)metal M; and 
 b) at least one organic polymer phase; 
 said process comprising polymerizing at least one monomer MM which comprises: 
 at least one first cationically polymerizable monomer unit A which has a metal or semimetal M, and 
 at least one second cationically polymerizable organic monomer unit B which is joined to the polymerizable unit A via one or more covalent chemical bonds, 
 under cationic polymerization conditions under which both the polymerizable monomer unit A and the polymerizable organic monomer unit B polymerize with breakage of the bond between A and B, 
 wherein the polymerization is performed in an aprotic solvent in which the nanocomposite material is insoluble, in the presence of at least one polymerization initiator and of at least one further substance selected from 
 α) at least one surface-active substance and 
 β) at least one particulate material, 
 or wherein the polymerization is performed in an aprotic solvent in which the nanocomposite material is insoluble, in the presence of at least one polymerization initiator, or the polymerization product is treated in the presence of at least one surface-active substance with a solution of a base in a protic solvent. 
 
     
     
       2. The process according to  claim 1 , wherein the polymerization of the at least one monomer MM is performed in the presence of at least one surface-active compound. 
     
     
       3. The process according to  claim 2 , wherein the surface-active compound has at least one hydrocarbon radical having at least 6 carbon atoms or at least one oligo- or poly(alkylsiloxane) group and at least one anionic or nonionic polar group. 
     
     
       4. The process according to  claim 3 , wherein the surface-active compound has at least one alkyl group having at least 6 carbon atoms and at least one sulfonate group. 
     
     
       5. The process according to  claim 2 , wherein the surface-active compound has at least one alkyl group having at least 6 carbon atoms and at least one cationically polymerizable group which is copolymerizable with the monomer unit A and/or B. 
     
     
       6. The process according to  claim 2 , wherein the surface-active compound is present in an amount of 0.5 to 50% by weight, based on the total amount of the monomers MM. 
     
     
       7. The process according to  claim 2 , wherein the surface-active compound is added before the polymerization initiator. 
     
     
       8. The process according to  claim 1 , wherein the polymerization of the at least one monomer MM is performed in the presence of at least one particulate material. 
     
     
       9. The process according to  claim 8 , wherein the particulate material has a primary particle size, determined by light scattering, in the range from 1 to 2000 nm. 
     
     
       10. The process according to  claim 8 , wherein the particulate material comprises at least a portion of the polymerization initiator. 
     
     
       11. The process according to  claim 8 , wherein the particulate material is a (semi)metal oxide. 
     
     
       12. The process according to  claim 11 , wherein the particulate material is a silica. 
     
     
       13. The process according to  claim 8 , wherein the particulate material is present in an amount of 1 to 10 000 parts by weight per 100 parts by weight of the at least one monomer MM. 
     
     
       14. The process according to  claim 8 , wherein the at least one monomer MM is added under polymerization conditions to a suspension of the particulate material in the organic solvent. 
     
     
       15. The process according to  claim 1 , wherein the polymerization is performed in an aprotic solvent in which the nanocomposite material is insoluble, in the presence of at least one polymerization initiator, and the polymerization product is treated in the presence of at least one surface-active substance with a solution of a base in a protic solvent. 
     
     
       16. The process according to  claim 15 , wherein the protic solvent is water. 
     
     
       17. The process according to  claim 15 , wherein the base is selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxides. 
     
     
       18. The process according to  claim 15 , wherein the surface-active substance has at least one alkyl group having at least 6 carbon atoms and at least one sulfonate group. 
     
     
       19. The process according to  claim 1 , wherein the metal or semimetal M is selected from the group consisting of B, Al, Si, Ti, Zr, Hf, Ge, Sn, Pb, V, As, Sb, Bi and mixtures thereof. 
     
     
       20. The process according to  claim 19 , wherein the metal or semimetal M of the monomer unit A comprises silicon in an amount of at least 90 mol%, based on the total amount of M. 
     
     
       21. The process according to  claim 1 , wherein the one or more monomer MM is described by the general formula I: 
       
         
           
           
               
               
           
         
         in which 
         M is a metal or semimetal; 
         R 1 ,R 2  may be the same or different and are each an Ar—C(R a ,R b )— radical in which Ar is an aromatic or heteroaromatic ring which optionally has 1 or 2 substituents selected from halogen, CN, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy and phenyl, and R a , R b  are each independently hydrogen or methyl or together are an oxygen atom or a methylidene group (═CH 2 ),
 or the R 1 Q and R 2 G radicals together are a radical of the formula A 
 
       
       
         
           
           
               
               
           
         
         
           in which A is an aromatic or heteroaromatic ring fused to the double bond, m is 0, 1 or 2, the R radicals may be the same or different and are selected from halogen, CN, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy and phenyl, and R a , R b  are each as defined above; 
         
         G is O, S or NH; 
         Q is O, S or NH; 
         q according to the valency of M is 0, 1 or 2, 
         X, Y may be the same or different and are each O, S, NH or a chemical bond; 
         R 1′ , R 2′  may be the same or different and are each C 1 -C 6 -alkyl, C 3 -C 6 -cycloalkyl, aryl or an Ar′—C(R a′ , R b′ )—radical in which Ar′ is as defined for Ar and R a′ , R b′  are each as defined for R a , R b , or R 1′ , R 2′  together with X and Y are a radical of the formula A, as defined above, 
         or, when X is oxygen, the R 1′  radical may be a radical of the formula: 
       
       
         
           
           
               
               
           
         
         in which q, R 1 , R 2 , R 2′ , Y, Q and G are each as defined above and # is the bond to X. 
       
     
     
       22. The process according to  claim 21 , wherein the one or more monomer MM to be polymerized comprises at least one monomer of the general formula II: 
       
         
           
           
               
               
           
         
         in which 
         M is a metal or semimetal; 
         A and A′ are each independently an aromatic or heteroaromatic ring fused to the double bond; 
         m and n are each independently 0, 1 or 2; 
         G and G′ are the same or different and are each independently O, S or NH; 
         Q and Q′ are the same or different and are each independently O, S or NH; 
         R and R′ are the same or different and are each independently selected from halogen, CN, C 1 -C 6 -alkoxy and phenyl; and 
         R a , R b , R a′ , R b′  are each independently selected from hydrogen and methyl, or R a  and R b  and/or R a′  and R b′  in each case together are an oxygen atom. 
       
     
     
       23. The process according to  claim 21 , wherein one or more monomer MM to be polymerized comprises at least one monomer of the general formula IV: 
       
         
           
           
               
               
           
         
         in which 
         M is a metal or semimetal; 
         Ar and Ar′ are the same or different and are each independently an aromatic or heteroaromatic ring which optionally has 1 or 2 substituents selected from the group consisting of halogen, CN, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy and phenyl; 
         R a , R b , R a′ , and R b′  each independently selected from hydrogen and methyl, or R a  and R b  and/or R a′  and R b′  in each case together are an oxygen atom; 
         q according to the valency of M is 0, 1 or 2; 
         X and Y may be the same or different and are each O, S, NH or a chemical bond; and 
         R 1′  and R 2′  may be the same or different and are each C 1 -C 6 -alkyl, C 3 -C 6 -cycloalkyl, aryl or an Ar″—C(R a″ ,R b″ )—radical in which Ar″ is as defined for Ar and R a′ , R b″  are each as defined for R a , R b , or R 1′ , R 2′  together with X and Y are a radical of the formula A as defined above. 
       
     
     
       24. The process according to  claim 23 , wherein one or more monomers of the formula IV is a compound of the general formula V: 
       
         
           
           
               
               
           
         
         wherein 
         M is a metal or semimetal; 
         Ar, Ar′ are the same or different and are each an aromatic or heteroaromatic ring which optionally has 1 or 2 substituents selected from halogen, CN, C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy and phenyl; 
         R a , R b , R a′ , R b′  are each independently selected from hydrogen and methyl, or R a  and R b  and optionally R a′  and R b′  in each case together are an oxygen atom; and 
         q according to the valency of M is 0, 1 or 2.